In electronic devices, power factor corrector (PFC) circuits are increasingly used to increase the power factor (PF) of AC electric power systems. In electronic power systems, a load with a low power factor draws more current than a load with a high power factor for the same amount of useful power transferred. When the power factor is low, the high current causes energy to be lost in the distribution system, requiring larger wires and other equipment capable of handling the higher current compared to a system with a higher power factor.
Because of the costs of larger equipment and wasted energy, electrical utilities will charge a higher cost to industrial or commercial customers who have a low power factor than to those who have a higher power factor. Power factor regulations are also becoming increasingly prevalent.
Power factor correction may be especially relevant for high power applications. At a high power, small differences in power factor can lead to significant cost savings. High power electronic power systems are becoming increasingly important in AC electric power systems.
A power factor corrector may be implemented using a switched-mode power supply. Power factor corrector circuits are generally optimized to have a high power factor for a particular switching frequency and load. However, applications often involve a load current that varies. Accordingly, there is a need for an active PFC circuit that can maintain a high power factor over a range of load currents.